Try my patched wish

Or, if you're lazy and are willing to try an .exe built by me
(Disclaimer: my PC is heavily infested by all sorts of computer
virus. By downloading these .exe and .dll files form this page,
you agree that I am not responsible for any damages caused by
these .exe and .dll files you download from this page.) Note this
is a patched Tk 8.3.2. tk832+w2kimepatch.zip.

Using Japanese Input in TK

After you finish the Control Panel setting (possible after a
reboot), you'd notice a new IME icon at he
lower-right corner of the screen. It initially displays , which stands for English input.

Start wish84.exe. Click on the console window to give it keyboard
focus.

Choose Japanese as your input language by
clicking on the icon
and choosing from the menu:

You notice the IME icon changes to indicate Japanese input. Also,
a new floating Japanese input bar is displayed on the screen.

Go to the Japanese input bar and choose the Hiragana (H)
input method:

Type the following keys in the wish console in the sequence:
n i h o n g
o. The text input will be changed to the Hiranaga
characters Ni, Ho, N, and Go, as in the following figure:

The same Hiranaga characters can have many meanings in
Japanese. You can type the SPACE key to choose the
desired meaning. In this exercise, type the SPACE key
once, it will display 3 Kanji characters Ni, Hon and Go, which
means "The Japanese Language", as in the following figure:

When the desired meaning is displayed, hit the Enter key to
accept the input. You will see that in the following
figure. Now you have completed the input of the 3 Kanji
characters here. You can then input more characters.

To switch back to English input, go to the IME icon and change it back
to

Note that the keys you type in steps 6, 7 and 8 are processed
by the input method editor. None of the keystrokes are sent to TK.
So you don't have to worry about processing these events.

Your TK app receives KeyPress events only when you confirm the
input (as in step 8). In our example, 3 KeyPress events are
received, one for each Kanji character.